Filter cartridge for water treatment device

ABSTRACT

A water filter cartridge including an outer shell, an inlet opening proximate a first end, an outlet opening and a cam extending axially from the first end. Cam is constructed and arranged so as to reset a mechanical flow totalization mechanism in a water treatment device. A channel and notch in the first end of the cartridge provide fluid communication to a chamber of a water treatment device.

[0001] This application is a continuation-in-part of application Ser.No. 08/203,380, filed Mar. 8, 1994.

FIELD OF THE INVENTION

[0002] This invention relates generally to water treatment devices, andmore particularly to devices incorporating mechanisms for end-of-lifeindication, automatic shutoff, resetting the automatic shutoff andbypass, and to a filter cartridge for water treatment devices.

BACKGROUND OF THE INVENTION

[0003] Water treatment devices for home and other use are well known inthe art. Such devices are incorporated into a water system eitherin-line or at a terminal end. An example of the former would be anunder-the-counter device which filters water prior to reaching thefaucet. There are two common types of terminal end devices-countertopand faucet-mounted. As compared to countertop and under-the-sinkdevices, designing a faucet-mounted device presents special challenges.These include making the device sufficiently light so that it can beattached to a faucet and sufficiently compact so that the device doesnot take up valuable sink space.

[0004] Water treatment devices can treat water by the use of mechanicalfiltration or chemical treatment. Mechanical filters treat water bypreventing passage of particulates. As a mechanical filter approachesthe end of its useful life, reduced or stopped flow due to particulateaccumulation provides a ready indication that element replacement isnecessary. By contrast, when the capacity of a chemical element isexceeded, there is no such indication. Chemical treatment isaccomplished by processes such as adsorption (e.g. charcoal media) andion exchange (e.g. for lead removal). Such chemical treatment eventuallydegrades and becomes inactive. However, no indication is provided to theuser that the water is no longer being treated by the media. exchange(e.g. for lead removal). Such chemical treatment eventually degrades andbecomes inactive. However, no indication is provided to the user thatthe water is no longer being treated by the media.

[0005] As a result, various approaches have been taken to indicate endof life to the user where it is not inherently provided by the behaviorof the filter media. One example is shown in U.S. Pat. No. 4,686,037. Inthis approach, a pre-filter is used to entrap contaminants, and thecolor of the pre-filter is compared by the user with a reference stripto determine when the media requires replacement. The problem with thisapproach, however, is that it is inherently subjective, and thereforesubject to error. Also, the user can easily forget to check thereference filter and mistakenly believe the media is still purifyingwhen it is not.

[0006] A much more accurate and foolproof means of indicating end oflife is through totalizing the volume which has passed through the mediaand automatically shutting off flow after a predetermined volume haspassed through the device. Although the flow totalization and shutoffvalve mechanisms required are relatively expensive and complex, this hasbecome recognized as the most accurate means of indicating end of life.For example, the certifying agency in the United States for watertreatment devices, the National Sanitation Foundation, requires forcertification of a rated volume, twice the filter media capacity when anautomatic shutoff is not used, and only 20% additional capacity when anautomatic shutoff is employed.

[0007] Both electrical and mechanical approaches to flow totalizationare known in the prior art. Examples of the former are shown in U.S.Pat. Nos. 4,918,426 and 5,089,144. In this approach, flow rate ismeasured by, for example, a pressure transducer and then integrated tocalculate total volume. After a predetermined volume has been reached, avalve is electrically actuated to stop flow.

[0008] Examples of mechanical totalization in water treatment devicesare shown in U.S. Pat. Nos. 4,681,677 and 4,698,164. In the mechanicalapproach, typically a turbine powered by water flowing through thedevice is interconnected with a series of gears which mechanically “addup” the volume of water which has passed through the device. In turn,the gearing mechanism is interconnected with a valve such that, after apredetermined volume of water has passed through the device, the valveis mechanically actuated to stop flow through the device.

[0009] However, prior art mechanical automatic shutoff mechanisms sufferfrom certain shortcomings. One problem is that the mechanisms employed,such as in the '677 patent, are too bulky to be included in a compactdevice. Another problem with prior art devices is that they makeresetting the totalization and shutoff mechanism unnecessarily difficultand/or expensive. For example, to reset the device shown in the '677patent, one would apparently have to manually release the valve from therotating cam and manually disengage the gearing mechanism to reset thetotalization mechanism to a zero volume position. In the '164 patent,the valve shutoff mechanism is incorporated into the replaceablecartridge, and the shutoff valve is connected to the gearing mechanismupon replacement of the cartridge. This approach is unnecessarilywasteful and expensive because the shutoff valve is thrown away witheach cartridge, rather than being reused.

[0010] With respect to faucet-mounted water treatment devices, it is notknown in the prior art to incorporate automatic shutoff end-of-lifeindication. This is due at least in part to the obstacles associatedwith incorporating a mechanical flow totalization and shutoff mechanismin the required compact size. As a result, prior art devices haveemployed much cruder forms of end-of-life indication, such as thatdiscussed above in the '037 patent. Not only are prior art end-of-lifeindicating devices much less accurate, but they are also unnecessarilywasteful due to the more frequent cartridge replacement often requiredby certification standards.

[0011] A feature that is common to faucet-mounted devices is the abilityto bypass or divert water from the filter media so that untreated watercan be obtained from the faucet. This is desirable because it avoidsunnecessary use of the filter media, allowing the user to bypass thewater treatment device if the water is not intended for drinking, as forexample for washing hands or dishes.

[0012] Such a bypass mechanism is shown in the '037 patent. In thisapproach, a separate handle is attached to the opposite end of themounting member to control a bypass valve. Other prior art devices usethis same approach, and therefore suffer from certain disadvantages. Theseparate handle adds unnecessary complexity and expense to manufacturinga bypass mechanism. Also, because of the environment in whichfaucet-mounted devices are employed, there is a significant problem withkeeping such devices clean. A separate handle only makes this moredifficult, adding increased surface area and creating difficult-to-cleancrevices. Finally, the added handle makes the appearance of the deviceless appealing, which is a particularly important concern forfaucet-mounted devices.

[0013] What has been needed is a compact, low-cost andeasy-to-manufacture water treatment device having an automatic shutoffmechanism which is easy to reset. What has also been needed is afaucet-mounted device incorporating automatic shutoff and a simplebypass mechanism.

[0014] What has also been needed is a replacement filter cartridge whichcan reset the flow totalization and shut-off mechanism upon replacementof the cartridge and which provides a simple water flow path andefficient sealing in communication with the water treatment device.

SUMMARY OF THE INVENTION

[0015] According to the present invention, a water treatment devicehaving a replaceable filter cartridge is provided. The filter cartridgecan include mechanical or chemical filter media or a combinationthereof.

[0016] In one aspect of the invention, the water treatment deviceincludes an arrangement comprising a mechanism for mechanicallytotalling the volume of water that has been filtered and a mechanism forindicating when the replaceable filter cartridge has reached the end ofits useful life. End of life indication is provided by a valve mechanismfor stopping flow after a predetermined volume has been filtered. Thearrangement also comprises a mechanism for resetting the flowtotalization mechanism, including a spring. The spring is connected withand biased by the flow totalization mechanism, and a mechanism forreleasing the spring to reset the flow totalization mechanism isincluded. The spring can be any of a variety of mechanical springs whichwould be suitable for this purpose, including for example torsional,coil, leaf, and helical springs in either compression or tension.

[0017] In another aspect of the invention, the water treatment deviceincludes an arrangement comprising a shutoff valve which closes to stopflow after a predetermined volume of water has passed through thecartridge. The arrangement further includes a spring which is loadedwhen the shutoff valve closes and a release arm which causes the springto unload and force the shutoff valve open during replacement of thefilter cartridge.

[0018] In another aspect of the invention, the water treatment deviceincludes an arrangement comprising a mechanism for mechanicallytotalling the volume of water that has been filtered and a mechanism forindicating end of life by stopping flow after a predetermined volume hasbeen filtered. A shutoff valve mechanism is permanently contained withinthe device such that it is not replaced upon replacement of the filtercartridge. The arrangement also comprises a mechanism for resetting theflow totalization mechanism, which includes a mechanism for resetting byreplacement of the filter cartridge.

[0019] The reset mechanisms of the present invention can be employed notonly in terminal-end water treatment devices, such as faucet-mounted andcounter-top, but also in in-line devices, such as under-the-counter.

[0020] In another aspect of the invention, the water treatment devicecomprises a faucet-mounted device. The faucet-mounted device comprises amechanism for indicating end of life by stopping flow of water throughthe filter cartridge after a predetermined volume of water has beenfiltered through the device.

[0021] In yet another aspect of the invention, the water treatmentdevice comprises a faucet-mounted device with a novel flow-bypassdesign. The faucet-mounted device comprises a housing with a filterelement contained therein and having inlet and outlet openings. Amounting member includes inlet and outlet ports, with the inlet portbeing attachable to the faucet. A valve is in operable connection withthe mounting member and the housing and includes first and second flowchannels. The first flow channel extends between the inlet port and theinlet opening, and the second flow channel extends between the inlet andoutlet ports. The valve body is rotatable with respect to the mountingmember between first and second flow positions. In the first flowposition, water flows from the inlet port, through the first flowchannel, into the inlet opening of the housing, through the filterelement and out the outlet opening of the housing. In the second flowposition, water flows from the inlet port, through the second flowchannel and out the outlet port of the mounting member. Therefore, byrotation of the housing, water is diverted from passing through thehousing to passing through the mounting member.

[0022] Also according to the present invention, a water filter cartridgefor use in a water treatment device is provided. In one aspect of theinvention, the water filter cartridge comprises an outer shellcontaining water treatment material and having a central axis. Thefilter cartridge further comprises an inlet opening proximate a firstend of the outer shell, an outlet opening proximate a second end, and acam extending axially from the first end of the outer shell. When thefilter cartridge is replaced, the cam resets the flow totalizationmechanism upon either insertion or withdrawal of the cartridge (orboth).

[0023] In another aspect of the invention, the water filter cartridgecomprises an outer shell, a radially displaced inlet opening proximate afirst end, and a generally coaxial outlet opening proximate a secondend. A channel and a notch in the first end are in fluid communicationwith one another so as to provided a flow path whereby water flows fromthe channel, through the notch, through a chamber of the water treatmentdevice, into the inlet opening of the filter cartridge and out theoutlet opening.

[0024] In yet another aspect of the invention, the water filtercartridge comprises an outer shell containing water treatment materialand having a longitudinal axis, an inlet opening and an outlet opening.An actuating projection extends from the outer shell generally parallelto the longitudinal axis of the outer shell. When the filter cartridgeis replaced, the actuating projection resets the flow totalizationmechanism upon either insertion or withdrawal of the cartridge (orboth).

[0025] These and other advantages and features of novelty whichcharacterize the invention are pointed out with particularity in theclaims annexed hereto. However, for a better understanding of theinvention and its advantages, reference should be made to the drawingswhich form a further part hereof, and to the accompanying descriptivematter in which there is illustrated and described a preferredembodiment of the invention.

BRIEF DESCRIPTION OF THE FIGURES

[0026]FIG. 1 is an exploded perspective view of a water treatment deviceaccording to the present invention;

[0027]FIG. 2 is a cross-sectional view of the water treatment deviceshown in FIG. 1 as viewed generally from Section 2-2 of FIG. 4;

[0028]FIG. 3 is a partial cross-sectional view of the water treatmentdevice shown in FIG. 1 as viewed from Section 3-3 of FIG. 5;

[0029]FIG. 4 is a top partial cross-sectional view of the flow shutoffmechanism of the present invention, with the mechanism in the zerovolume position;

[0030]FIG. 5 is a top partial cross-sectional view of the flow shutoffmechanism of the present invention, with the flow shutoff mechanism atthe end-of-life position;

[0031]FIG. 6 is a top partial cross-sectional view of the flow shutoffmechanism of the present invention, with the flow shutoff mechanism inan intermediate position and the reset mechanism of the presentinvention activated;

[0032]FIG. 7 is a cross-sectional view of a bypass mechanism accordingto the present invention, with the flow diverted through the mountingmember;

[0033]FIG. 8 is an end cross-sectional view of the flow-bypass mechanismshown in FIG. 7 as viewed from Section 8-8 of FIG. 7; and

[0034]FIG. 9 is a partial cross-sectional view of a second embodiment ofa water treatment device and replacement filter cartridge according tothe present invention, having improved sealing between the watertreatment device and the inlet opening of the replacement filtercartridge.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0035] Referring now to the drawings wherein like numerals designatelike parts, a faucet-mounted water treatment device 10 is shown in FIGS.1-8. Although water treatment device 10 is faucet mounted, many of thenovel features disclosed herein can be incorporated into in-line orcountertop devices as well.

[0036] Referring to FIGS. 1 and 2, water treatment device 10 includeshousing 20 which comprises upper portion 22 and cap 24 which threadsinto upper portion 22. First O-ring 26 is provided in channel 28 tocreate a watertight seal between upper portion 22 and cap 24.Replaceable filter cartridge 40 is inserted into upper portion 22 frombelow, and cap 24 is threaded to upper portion 22 to secure cartridge 40in housing 20.

[0037] Water flows through housing 20 and cartridge 40 as follows. Waterenters housing 20 from valve body 30 at inlet opening 21 and fillsannular space 60 between cartridge 40 and housing 20, includingperipheral annular channel 62 formed in top 52 of cartridge 40. As bestshown in FIGS. 1 and 3, water then flows from channel 62, into notch 64of top 52 and up through cylindrical portions 72, 82 of lower 70 andupper 80 plates, respectively. Water is then directed out of jet 92 oftop plate 90 (best shown in FIG. 1) to turn blades 102 of turbine 100.Turbine 100 is tightly nested in top plate 90, as best shown in FIG. 2,with minimum clearance between blades 102 and top plate 90 to maximizeturbine efficiency. Water exits turbine 100 and passes through exitcylinder 94 of top plate 90, which extends over second cylindricalportion 84 of upper plate 80.

[0038] In normal operation (i.e. when flow has not been “shut off”),water then flows into cartridge 40 through inlet opening 66 in top 52.While water primarily flows as described due to the arrangement of thevarious parts, it should be understood that water also fills chamber 68generally defined between lower plate 70 up to upper portion 22 ofhousing 20. Water flows through cartridge 40 by passing through filterdisc 43, second screen 55, first media 42, first screen 54, second media44, and post filter 56, respectively, and then out through holes 49 inretainer 48. Water then exits housing 20 from outlet opening 29. It willbe understood that outlet opening 29 could take on variousconfigurations and could be from various positions in housing 20,although it is preferable that opening 29 be from bottom of housing 20.

[0039] Mounting member 110 is used to mount water treatment device 10 toa faucet (not shown). Adapter nut 112 defines inlet port 113 and isconnected to body 114 by screen 116, which is shouldered by adaptor nut112 and sealingly held in annular channel 115 of body 114. Aerator 118and aerator nub 120 are inserted into body 114 from below, with aerator118 defining outlet port 119. Mounting member body 114 extends overvalve body 30, and they are sealed together by third 122, fourth 123 andfifth 124 O-rings. Fifth O-ring 124 surrounds extension 126 of body 114,which extends into axial channel 34 of valve body 30. Axial channel 34is preferably tapered for ease of manufacturing by injection molding.

[0040] Valve body 30 is rotatable within mounting member 110 between twoflow positions to allow the user to bypass cartridge 40 if desired. Inthe first flow position shown in FIG. 2, water flows from inlet port113, through first flow channel 32 defined by radial 33 and axial 34channels and into inlet opening 21 of housing 20. In the second flowposition shown in FIGS. 7 and 8, water flows from inlet port 113,through C-shaped second channel 36 and out outlet port 119 of mountingmember 110. It will be understood by those skilled in the art that first32 and second 36 channels can be configured in a variety of other waysto achieve the result of diverting flow by rotation of housing 20. Itwill also be understood that it is not required that valve body 30 bemolded as a single part with upper portion 22 of housing 20 as in thepreferred embodiment, although it is required that valve body 30 befixedly connected to housing 20.

[0041] Water treatment device 10 includes an arrangement 15 forindicating the useful life remaining in replaceable filter cartridge 40.Arrangement 15 includes flow totalization mechanism 130 and shutoffvalve mechanism 150. It will be understood by those skilled in the artthat a variety of totalization 130 and valve 150 mechanisms could beemployed within the scope of the present invention to achieve the samepurpose. Arrangement 15 also includes reset mechanism 160 for resettingtotalization 130 and valve 150 mechanisms. In the preferred embodimentreset mechanism 160 includes biased spring 162 which is released byinsertion of cartridge 40. However, it will be understood by thoseskilled in the art that spring 162 could be released by other means. Itwill also be understood that totalization 130 and valve 150 mechanismscould be reset by a variety of other mechanisms responsive to insertionof cartridge 40 which do not incorporate a spring.

[0042] In the preferred totalization mechanism 130, turbine 100 isconnected with a plurality of gears 132 which in turn are connected witha rotating sector 140. It will be understood that turbine 100 need notbe directly connected to first gear 134 and that sector 140 need not bedirectly connected to last gear 136. Gears 132 are successivelyinterconnected, with each having a 10-to-1 ratio in the preferredembodiment. Turbine 100 and two gears 132 are stacked on first pin 138,and the remaining three gears 132, including first 134 and last 136gears are stacked on second pin 139. Pins 138, 139 are held in placefrom above by upper portion 22 of housing 20. From below, first pin 138is inserted into a hole in upper plate 80, and second pin 139 is held inplace by last gear 136, which extends through and is seated on raisedportion 86 of upper plate 80.

[0043] Last gear 136 is connected to sector 140 by pinion 137 of lastgear 136 engaging teeth 142 of sector 140, as best shown in FIGS. 4 and5. Thus, as turbine 100 rotates, gears 132 are successively rotated,causing sector 140 to be rotated by pinion 137 and thereby “adding up”the volume of water that has passed through cartridge 40.

[0044] The preferred shutoff valve mechanism 150 includes ball 152,which is held by and rotated with sector 140, and flow inlet opening 66of filter cartridge 40. Shutoff mechanism 150 starts in a zero volumeposition, as shown in FIGS. 2 and 4. After totalization mechanism 130has rotated sector 140 to the flow stop position, as shown in FIGS. 3and 5, ball 152 becomes seated in inlet opening 66 of cartridge 40,which is formed by raised portion 51 of top 52 extending through lowerplate 70. It will be understood by those skilled in the art that avariety of other suitable mechanical valve mechanisms could also beemployed.

[0045] Reset mechanism 160 includes spring 162 which is connected to andwound by sector 140 as sector 140 rotates. It will be understood that,while the preferred embodiment employs a wound coil spring 162, numerousother types of springs as discussed hereinabove and a variety of otherarrangements and connections could be employed whereby a spring isbiased by a flow totalization mechanism. To release spring 162 in thepreferred embodiment, pinion 137 is radially disengaged from teeth 142of sector 140, thereby causing sector 140 to be rotated back to the zerovolume position by spring 162, as shown in FIG. 6. It will be understoodthat teeth 142 and pinion 137 could also is be separated axially toachieve the same result.

[0046] In the preferred embodiment, spring 162 is released by atransverse movement of slide 164 acting as a release arm. Slide 164includes vertical extension 165 onto which sector 140 and spring 162 arerotatably mounted. Spring 162 includes levers 163 extending fromopposite ends, with one of levers 163 abutting stop 144 on sector 140and the other lever 163 abutting fixed stop 74 on lower plate 70. Thisarrangement allows spring 162 to serve both the functions of resettingsector 140 and returning slide 164 to its unslid position because spring162 resists torsional movement of sector 140 as well as transversemovement of slide 164. Slide 164 is held in line by guides 76 on lowerplate 70. The components between upper 80 and lower 70 plates are heldtogether by screws 88 inserted from below, as shown in FIG. 1.

[0047] In the preferred embodiment, slide 164 is slid by insertion andremoval of filter cartridge 40. It will be understood that slide 164could be moved in a variety of other ways, such as by pushing a buttonto reset totalization mechanism 130. It will also be understood thattotalization mechanism 130 could also be reset by a variety of othermechanisms which are responsive to replacement of cartridge 40. Forexample, a mechanism could be constructed such that insertion ofcartridge 40 causes last gear 136 to axially separate from sector 140,or that causes separation and turning of sector 140 without use of aspring 164.

[0048] In the preferred arrangement, slide 164 is slid by cam 53projecting axially from top 52 of cartridge 40, thus actuating resetmechanism 160. When cartridge 40 is axially inserted into housing 20,cam extends through opening 78 in lower plate 70 and abuts cam followersurface 166 on slide 164 to move slide 164 transversely. Those skilledin the art will recognize that cam 53 need not necessarily be a separateprojection, but can form part of for example an inlet or outlet openingprojecting from the cartridge to actuate reset mechanism 160. Cam 53includes a double sloping facade facing radially inwardly. Although cam53 can take on a variety of other shapes, in the preferred embodimentthe sloped facade is generally symmetric. As a result, slide 164 is slidtransversely both upon insertion and removal of cartridge 40.Necessarily therefore, while totalization mechanism 130 in normaloperation will already be returned to a zero volume position uponremoval of cartridge 40, the mechanism 130 is “reset” through transversemovement of slide 164 by both insertion and withdrawal of cam 53 in thepreferred design. Within the principles of the invention, however, thecam could be designed so as to reset the flow totalization mechanismupon either insertion or removal or both.

[0049] In addition to providing a flow stop indication of end of life, acontinuous visual indication of the amount of useful life remaining inreplaceable filter cartridge 40 is provided in the preferred embodiment.This is accomplished by colored screen 146 at the end of sector 140,which is visible through lens 170 as sector 140 rotates. Referring toFIG. 1, lens 170 is inserted into slot 23 of upper portion 22 of housing20, and is sealed by gasket 171.

[0050] In the preferred embodiment, cartridge 40 comprises two chemicalfilter media, including first media 42, which comprises an ion exchangeresin suitable for removing lead, and second media 44, which comprisesGranular Activated Charcoal (“GAC”). Mechanical or other chemical filtermedia can also be employed within the scope of the invention in variousnumbers or combinations. In the preferred cartridge 40, media 42, 44 areenclosed by base 46, O-ring retainer 48 which is friction fit with aninwardly extending cylindrical portion 50 of base 46, and top 52 whichis friction fit with an inner side of the upper portion of base 46. Base46 includes shoulder 47 which is supported by cap 24 to push cartridge40 upwardly into housing 20. Retainer 48 holds second O-ring 27 in placeto create a seal between retainer 48, cylindrical portion 50 and inwardextension 25 of cap 24. Water exits cartridge 40 through holes 49 inretainer 48.

[0051] Within cartridge 40, filter media 42, 44 (not shown in FIG. 1)are separated by first screen 54, and second screen 55 separates firstmedia 42 from filter disc 43 which is held between top 52 and secondscreen 55. Filter disc 43 is made of white filter paper and is for thepurpose of providing the user with a visual reference to assure the userthat cartridge 40 is performing its function and to indicate whether aparticular cartridge has been used. In the preferred embodiment, top 52is clear so that the user can see if disc 43 has gathered contaminants,indicating that the cartridge 40 has been used. U-shaped post filter 56extends over cylindrical portion 50 to prevent GAC from being flushedout, and post filter cap 57 extends over filter 56 to direct the flow ofwater to bottom of cartridge 46 to assure that the entire second media44 is utilized.

[0052] Water flows through cartridge 40 as follows. Unfiltered waterfills peripheral annular channel 62 in top 52 and then into notch 64from which it flows upwardly through cylindrical portion 72 of lowerplate 70. Those skilled in the art will recognize that channel 62 andnotch 64 could take on a variety of other shapes to provide fluidcommunication between the periphery of top 52 and the semi-circularportion of notch 64. For example, channel 62 could extend across top 52to reach notch 64, and channel 62 need not necessarily be open but couldpass through top 52 under the surface. Further, annular channel 62 neednot extend entirely around the periphery of top 52 and could have anenclosing outer wall. Notch 64 preferably has a semi-circular shape toprovide optimal fluid communication with cylindrical portion 72 of lowerplate 70. The remaining flow passage portion of notch 64 connects thesemi-circular portion with annular channel 62 in the preferredembodiment and could be shaped in a variety of ways to suit thispurpose.

[0053] Referring now to FIG. 9, a second embodiment having improvedmating between top 52 of cartridge 40 and lower plate 70, which encloseschamber 68, is shown. Ideally, all of the water entering inlet opening66 of cartridge 40 should come from chamber 68. Otherwise water leakingfrom between lower plate 70 and cartridge top 52 into chamber 68 willhave bypassed the flow totalization mechanism 130 causing totalizationinaccuracies (i.e., under-totalization) relative to the volume of wateractually filtered. Therefore, the preferred design includes a structurewhich provides better sealing between lower plate 70 and inlet opening66 of filter cartridge 40. In the preferred design, lower plate 70includes an annular wall 200 which extends toward top 52 of cartridge40. A corresponding second annular wall 201 extends into opening 78 oflower plate 70, with the outer diameter of second annular wall 201providing a friction fit with the inner diameter of first annular wall200. Annular walls 200, 201 are preferably tapered for mating engagementto provide better sealing First annular wall 200 of top 52 extends intoannular channel 203 formed in top 52 and surrounding second annular wall201 This permits contact between annular walls 200, 201 along anincreased distance as well as provides a positive indication of matingbetween lower plate 70 and top 52 of cartridge 40.

[0054] It should be understood that the present invention is not limitedto the preferred embodiment discussed above, which is illustrative only.Changes may be made in detail, especially matters of shape, size,arrangement of parts, or material of components within the principles ofthe invention to the full extent indicated by the broad general meaningsof the terms in which the appended claims are expressed.

What is claimed is:
 1. A water filter cartridge for use in a watertreatment device having a mechanical totalization mechanism, a shut-offvalve mechanism which stops the flow of water after a predeterminedvolume of water has been filtered, and a flow totalization resetmechanism, the water filter cartridge comprising: (a) an outer shellcontaining water treatment material and having a central axis; (b) aninlet opening proximate a first end and an outlet opening proximate asecond end of said outer shell; (c) a cam extending axially from saidfirst end of said outer shell, such that, when the filter cartridge isproperly inserted into or withdrawn from the water treatment device,said cam resets the flow totalization mechanism.
 2. A water filtercartridge as defined in claim 1, wherein said cam includes a doublesloping facade facing generally radially inward toward said centralaxis, said facade actuating said flow totalization reset mechanism uponaxial insertion or withdrawal of said filter cartridge.
 3. A waterfilter cartridge as defined in claim 1, wherein said shell includes aseparate top which defines said first end and includes said inletopening and said axially extending cam.
 4. A water filter cartridge asdefined in claim 1, wherein said cam and said inlet opening are radiallydisplaced from said central axis along respective radial lines and saidradial lines are approximately 90° apart relative to one another.
 5. Awater filter cartridge for use in a water treatment device having achamber, comprising: (a) an outer shell containing water treatmentmaterial and having a central axis; (b) an inlet opening proximate afirst end of said outer shell, said inlet opening being radiallydisplaced from said central axis; (c) an outlet opening proximate asecond end of said outer shell, said outlet opening being generallyco-axial with said central axis; (d) a channel in said first end; (e) anotch in said first end, said notch being radially displaced from saidcentral axis in a direction opposite said radial displacement of saidinlet opening, and said notch being in fluid communication with saidchannel; (f) whereby water flows from said channel, through said notch,through the chamber of the water treatment device, into said inletopening, through said water treatment material and out said outletopening.
 6. A water filter cartridge as defined in claim 5, wherein saidchannel is annular and generally extends at least partially along aperiphery of said first end and said notch extends generally to saidperiphery so as to fluidly communicate with said annular channel.
 7. Awater filter cartridge as defined in claim 6, wherein said annularchannel extends along the entire periphery of said first end.
 8. A waterfilter cartridge as defined in claim 6, wherein said notch includes agenerally semi-circular portion and a flow passage portion extending andproviding fluid communication between said annular channel and saidgenerally semi-circular portion, said generally semi-circular portionproviding improved fluid flow with the chamber of the water treatmentdevice.
 9. A water filter cartridge as defined in claim 5, the watertreatment device having a plate generally enclosing the chamber, theplate including an opening defined by a first annular wall having aninner diameter, wherein said first end of said outer shell includes asecond annular wall defining said inlet opening of the cartridge, saidsecond annular wall extending into the plate opening and having anoutside diameter approximately equal to the inner diameter of the plateopening, thereby sealing the plate with said inlet opening of the filtercartridge.
 10. A water filter cartridge as defined in claim 9, whereinan inner side of the first annular wall and an outer side of said secondannular wall are tapered for mating engagement so as to provide improvedsealing between the filter cartridge and the chamber of the watertreatment device.
 11. A water filter cartridge as defined in claim 9,wherein said first end includes an annular channel surrounding saidsecond annular wall, with the first annular wall of the plate extendinginto said annular channel to provide better mating between the plate andthe filter cartridge.
 12. A water filter cartridge for use in a watertreatment device having a mechanical totalization mechanism, a shut-offvalve mechanism which stops the flow of water after a predeterminedvolume of water has been filtered, and a flow totalization resetmechanism, the water filter cartridge comprising an outer shellcontaining water treatment material and having a longitudinal axis, aninlet opening, an outlet opening, and an actuating projection extendingfrom said outer shell generally parallel to said longitudinal axis ofsaid outer shell, such that, when the filter cartridge is properlyinserted into or withdrawn from the water treatment device, saidactuating projection resets the flow totalization mechanism.